1. Field of the Invention
The present invention relates to a technology for preventing dust or the like from being contained in a product such as an optical product.
2. Description of Related Art
Japanese Unexamined Patent Publication (Kokai) No. 2000-202862 discloses a prior art in the above technical field. Japanese Unexamined Patent Publication (Kokai) No. 2000-202862 discloses an apparatus for producing a disk substrate made of resin, in which a molten resin material is injected into a cavity formed between a pair of dies, and the resin material is cooled and solidified to produce a disk substrate, wherein there are provided a disk substrate forming portion provided with upper and lower openings, in which the dies are disposed, and an air supplying portion for supplying clean air to the disk substrate forming portion; the clean air is supplied from the air supplying portion to the disk substrate forming portion via the upper opening of the disk substrate forming portion and, then, passes through the portion of the disk substrate forming portion, in which the dies are disposed, and is discharged to the outside of the disk substrate forming portion via the lower opening of the disk substrate forming portion.
However, when a disk substrate is formed, as a molded product is removed from the dies by a removing machine which can access the upper or side portion of the dies, it is unnecessary to provide an opening in the lower portion of the disk substrate forming portion. Accordingly, the lower portion of the disk substrate forming portion may be closed, or a die-temperature controller or the like may be disposed on the lower portion of the disk substrate forming portion. In such a case, a flow of the clean air toward the lower portion of the disk substrate forming portion is obstructed and, accordingly, dust deposits on the die and is included in a molded product.